Some factors influencing the morphology of α-zirconium phosphate and its intercalation reactions with a bifunctional thioether amine

Crystalline samples of α-zirconium phosphate, (α-ZrP, α-Zr(HPO₄)₂·H₂O) have been prepared decomposition of zirconium fluoride complexes in the presence of phosphoric acid under a variety of conditions. The crystallinity and morphology have been shown to depend on a number of factors including the F^-/Zr⁴⁺ ratio, the concentration of Zr⁴⁺ ions, the material of the reaction vessel and the reaction temperature. Under conditions of rapid precipitation small plate-like crystals of α-ZrP are produced whereas under conditions of slow crystallisation larger crystals with a lower aspect ratio are formed. The relative intensities of the d₀₀₂, d₁₁₀ and d₁₁₂ reflections observed by X-ray powder diffraction show a correlation with the crystal morphology as determined by SEM. The intercalation reaction of 4-(methylmercapto)aniline with different samples of α-ZrP under a variety of conditions has been studied. Incomplete intercalation is observed in each case, with the extent of intercalation depending on both the morphology of the α-ZrP and the reaction conditions. The intercalated amine has been shown to exist as a mixture of protonated cations and neutral molecules.